U.S. patent application number 13/415905 was filed with the patent office on 2012-09-13 for image pickup apparatus having lens array and image pickup optical system.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. Invention is credited to Koshi Hatakeyama, Norihito Hiasa.
Application Number | 20120229691 13/415905 |
Document ID | / |
Family ID | 46026242 |
Filed Date | 2012-09-13 |
United States Patent
Application |
20120229691 |
Kind Code |
A1 |
Hiasa; Norihito ; et
al. |
September 13, 2012 |
IMAGE PICKUP APPARATUS HAVING LENS ARRAY AND IMAGE PICKUP OPTICAL
SYSTEM
Abstract
An image pickup apparatus (301) includes an image pickup element
(103), a lens unit (101) configured to collect a ray from an object
(201) on an image-side conjugate plane (202), and a lens array
(102) that includes a plurality of lens cells, and that is disposed
so that the image-side conjugate plane (202) and the image pickup
element (103) are conjugate to each other, and the lens array (102)
is disposed so as to meet a predetermined conditional
expression.
Inventors: |
Hiasa; Norihito;
(Utsunomiya-shi, JP) ; Hatakeyama; Koshi; (Tokyo,
JP) |
Assignee: |
CANON KABUSHIKI KAISHA
Tokyo
JP
|
Family ID: |
46026242 |
Appl. No.: |
13/415905 |
Filed: |
March 9, 2012 |
Current U.S.
Class: |
348/340 ;
348/E5.045 |
Current CPC
Class: |
H04N 5/2355 20130101;
G02B 27/0075 20130101; H04N 5/2254 20130101 |
Class at
Publication: |
348/340 ;
348/E05.045 |
International
Class: |
H04N 5/225 20060101
H04N005/225 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2011 |
JP |
2011-052352 |
Claims
1. An image pickup apparatus comprising: an image pickup element; a
lens unit configured to collect a ray from an object on an
image-side conjugate plane; and a lens array that includes a
plurality of lens cells, wherein the lens array is disposed so that
the image-side conjugate plane and the image pickup element are
conjugate to each other, and wherein the following expression is
met: 0.05 < .sigma. 1 P ex < 0.95 ##EQU00014## where
.sigma..sub.1 is a distance from an object-side principal plane of
the lens array to the image-side conjugate plane, and P.sub.ex is a
distance from en exit pupil of the lens unit to the image-side
conjugate plane.
2. The image pickup apparatus according to claim 1, wherein the
lens array is disposed so that pixels projected onto the image-side
conjugate plane by adjacent lens cells are shifted each other by a
length different from an integer multiple of a pitch of the
projected pixels when the pixels of the image pickup element are
projected onto the image-side conjugate plane via the lens
cells.
3. The image pickup apparatus according to claim 1, wherein the
following expression is met: 0.9 < M m mod ( .DELTA. LA .sigma.
2 .DELTA..sigma. 1 , 1 ) < 1.1 ##EQU00015## where .sigma..sub.2
is a distance from an image-side principal plane of the lens, array
to the image pickup element, .DELTA. is a pixel pitch of the image
pickup element, .DELTA..sub.LA is a pitch of the lens array, M is
an integer that meets the following expression: 0.2 < M 1 +
.sigma. 1 / .sigma. 2 < 2.0 ##EQU00016## and m is an integer
that is smaller, than M and the greatest common factor of m and M
is 1.
4. The image pickup apparatus according to claim 1, wherein an
image-side surface of the lens cell has a convex shape.
5. The image pickup apparatus according to claim 1, wherein an
object-side surface of the lens cell has a plane or a convex
shape.
6. The image pickup apparatus according to claim 1, wherein the
lens array is disposed at an object side relative to the image-side
conjugate plane of the lens unit.
7. An image pickup optical system that collects a ray from an
object on an image pickup element, comprising: a lens unit
configured to collect the ray from the object on an image-side
conjugate plane; and a lens array that includes a plurality of lens
cells, wherein the lens array is disposed so that the image-side
conjugate plane and the image pickup element are conjugate to each
other, and wherein the following expression is met: 0.05 <
.sigma. 1 P ex < 0.95 ##EQU00017## where .sigma..sub.1 is a
distance from an object-side principal plane of the lens array to
the image-side conjugate plane, and P.sub.ex is a distance from en
exit pupil of the lens unit to the image-side conjugate plane.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an image pickup apparatus
having a lens array, and an image pickup optical system.
[0003] 2. Description of the Related Art
[0004] Recently, it has been proposed for image pickup apparatus to
perform calculations using data obtained by an image pickup element
and to perform digital image processing in accordance with the data
to output various kinds of images. A "Plenoptic 2.0 Camera" that
simultaneously obtains a two-dimensional light intensity
distribution and parallax information on an object plane
(collectively, "light field") using "Light Field Photography" is
disclosed in the literature, Todor Georgiev, et al., "Full
Resolution Light Field Rendering", Adobe Technical Report January
2008, and Todor Georgiev, et al., "Superresolution with Plenoptic
2.0 Camera", 2009 Optical Society of America. According to such
image pickup apparatuses, a focus position of an image, a depth of
field, or the like can be changed by obtaining a light field and
then performing image processing after taking the image.
[0005] However, the image pickup apparatus needs to use a pixel of
the image pickup element for storing the parallax information in
addition to storing the two-dimensional light intensity
distribution. Therefore, spatial resolution deteriorates compared
to an image pickup apparatus that stores only the two-dimensional
light intensity distribution. A configuration in which a certain
point on an image plane formed by a main lens unit is imaged at a
different pixel position by each lens (sometimes referred to as a
"micro-lens") of a lens array is disclosed in the literature, Todor
Georgiev, et al., "Superresolution with Plenoptic 2.0 Camera", 2009
Optical Society of America. A plurality of small images obtained in
this way are reconstructed to obtain a high-resolution
reconstructed image. This method of obtaining a high-resolution
image is referred to as a "pixel shift effect".
[0006] However, the specific configuration that is needed in order
to obtain high resolution is not disclosed in the literature, Todor
Georgiev, et al., "Superresolution with Plenoptic 2.0 Camera", 2009
Optical Society of America.
SUMMARY OF THE INVENTION
[0007] The present invention provides an image pickup apparatus and
an image pickup optical system that are capable of obtaining a
high-resolution light field in a simple configuration.
[0008] An image pickup apparatus as one aspect of the present
invention includes an image pickup element, a lens unit configured
to collect a ray from an object on an image-side conjugate plane,
and a lens array that includes a plurality of lens cells and that
is disposed so that the image-side conjugate plane and the image
pickup element are conjugate to each other, and the lens array is
disposed so as to meet a predetermined conditional expression.
[0009] An image pickup optical system as another aspect of the
present invention is an image pickup optical system that collects a
ray from an object on an image pickup element and that includes a
lens unit configured to collect the ray from the object on an
image-side conjugate plane, and a lens array that includes a
plurality of lens cells and that is disposed so that the image-side
conjugate plane and the image pickup element are conjugate to each
other, and the lens array is disposed so as to meet a predetermined
conditional expressions.
[0010] Further features and aspects of the present invention will
become apparent from the following description of embodiments with
reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic configuration diagram of the image
pickup optical system in Embodiments 1, 3, and 4.
[0012] FIG. 2 is a schematic configuration diagram of the image
pickup optical system in Embodiment 2.
[0013] FIG. 3 is a block diagram of an image pickup apparatus in
each of the present embodiments.
[0014] FIGS. 4A to 4C are diagrams of describing a pixel shift
effect in each of the present embodiments.
[0015] FIG. 5 is a diagram of describing an arrangement of the
image pickup optical system in each of the present embodiments.
[0016] FIGS. 6A and 6B are diagrams of describing an image on an
image pickup element in the present embodiment.
[0017] FIG. 7 is a diagram of indicating a pixel shift amount with
respect to a distance .sigma..sub.1.
[0018] FIG. 8 is a diagram indicating a ratio of pixel shift with
respect to distance .sigma..sub.1.
[0019] FIG. 9 is a diagram describing the overlap number of small
lenses in each of the present embodiments.
[0020] FIG. 10 is a diagram of describing a spatial resolution
including the pixel shift effect in each of the present
embodiments.
[0021] FIG. 11 is a diagram of indicating a relationship between
distance .sigma..sub.1 and spatial resolution ratio.
[0022] FIG. 12 is a cross-sectional diagram of the image pickup
optical system in Embodiment 1.
[0023] FIG. 13 is a cross-sectional diagram of the image pickup
optical system in Embodiment 2.
[0024] FIG. 14 is a cross-sectional diagram of the image pickup
optical system in Embodiments 3 and 4.
[0025] FIG. 15 is a configuration diagram of the image processing
system in Embodiment 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Embodiments of the present invention will be described below
with reference to the accompanied drawings. In each of the
drawings, the same elements will be denoted by the same reference
numerals and the duplicate descriptions thereof will be omitted.
Each of the embodiments of the present invention described below
can be implemented solely or as a combination of a plurality of the
embodiments or features thereof where necessary or where the
combination of elements or features from individual embodiments in
a single embodiment is beneficial.
[0027] The image pickup apparatus of the present embodiment is
configured so as to obtain a light field using a lens array, and
the lens array is disposed at an appropriate position to achieve an
efficient high-resolution. First of all, referring to FIGS. 1 and
2, a schematic configuration of the image pickup apparatus (and an
image pickup optical system that is configured by excluding an
image pickup element from the image pickup apparatus) will be
described. FIG. 1 is a schematic configuration diagram of an image
pickup optical system in Embodiments 1, 3, and 4 described below,
and FIG. 2 is a schematic configuration diagram of an image pickup
optical system in Embodiment 2 described below.
[0028] As illustrated in FIGS. 1 and 2, the image pickup optical
system has a main lens unit 101 (an optical system) that is
provided with an aperture stop (not shown). In FIG. 2, a lens array
102 and an image pickup element 103 are disposed at a rear side (at
an image side) of an imaging plane, i.e. an image-side conjugate
plane 202 of the image lens unit 101 with respect to an object
plane 201. The lens array 102 is disposed so that the image-side
conjugate plane 202 of the main lens unit 101 and the image pickup
element 103 correspond to a pair of conjugate planes of the lens
array 102.
[0029] A ray from the object plane 201 enters the image pickup
element 103 via the main lens unit 101 and the lens array 102. In
this case, a real image that is formed by the main lens unit 101,
i.e. that is formed by a light collection function, is reformed by
the lens array 102, and it enters a plurality of different pixels
of the image pickup element 103 in accordance with a position and
an angle of the ray, on the object plane 201. As a result, the
image pickup element 103 obtains an image that is configured by a
plurality of small images which have different imaging viewpoints
and imaging ranges. On the other hand, in FIG. 1, the lens array
102 is disposed at a front side relative to the imaging plane of
the main lens unit 101, i.e. at an object side of an image-side
conjugate plane 202 of the main lens unit 101 with respect to the
object plane 201, to obtain the light field. In any cases, however,
the image of the main lens unit 101 with respect to the object
plane 201 is viewed as an object by the lens array 102 to be formed
on the image pickup element 103, and therefore those are
essentially the same.
[0030] Next, referring to FIG. 3, a configuration of the image
pickup apparatus in the present embodiment will be described. FIG.
3 is a block diagram of the image pickup apparatus in the present
embodiment. The image pickup element 103 is a two-dimensional image
pickup element such as a CCD (Charge Coupled Device) or a CMOS
(Complementary Metal-Oxide Semiconductor). The energy of the ray
that enters the image pickup element 103 via the main lens unit 101
and the lens array 102 is changed to an electric signal (an analog
signal) to be converted into a digital signal by an A/D convertor
109. A predetermined processing is performed for this digital
signal by an image processor 105, and the digital signal is stored
in an image recording medium 110 such as a semiconductor memory in
a predetermined format. In this case, image pickup condition
information of the image pickup apparatus that is obtained from a
state detector 108 is stored at the same time. The image pickup
condition information is for example an object distance, a stop, or
a focal length in a zoom lens. The state detector 108 may directly
obtain the image pickup condition information from a system
controller 111, or alternatively it can also obtain information
related to the image pickup optical system from an optical system
controller 107.
[0031] When the image stored in the image recording medium 110 is
displayed on a display 106, a reconstruction processing is
performed by the image processor 105 based on the image pickup
condition information. As a result, an image reconstructed to be a
desired viewpoint, focus position, or depth of field is displayed
on the display 106. For speeding up the processing, a desired image
setting such as a viewpoint, a focus, or a depth of field may also
be previously stored in a storage unit 109 to directly display the
reconstructed image without involving the image recording medium
110. Furthermore, the image that is recorded in the image recording
medium 110 may also be a reconstructed image. The series of
controls described above are performed by the system controller
111, and a mechanical drive of the image pickup optical system is
performed by the optical system controller 107 in accordance with
an instruction of the system controller 111.
[0032] Subsequently, an appropriate position of the lens array 102
will be described. First of all, the deterioration of the
resolution in accordance with obtaining the light field is
described, and next an optimal condition for obtaining the high
resolution by the pixel shift effect is obtained. A condition that
suppresses a sensitivity of the arrangement of the lens array 102
for the pixel shift effect is also described. For easy
understanding, the following calculation is performed for a
one-dimensional arrangement. The same is true for a two-dimensional
arrangement.
[0033] First of all, referring to FIGS. 4A to 4C, the deterioration
of the resolution of the image pickup optical system that obtains
the light field will be described. FIGS. 4A to 4C are diagrams of
describing the pixel shift effect in the present embodiment, which
is depicted by extracting a part of FIG. 2. Dashed lines in FIGS.
4A to 4C indicate angle of field with respect to each small lens,
i.e. a lens cell, of the lens array 102. In a conventional image
pickup optical system that obtains only a two-dimensional light
intensity distribution, an image pickup element is disposed on an
image-side conjugate plane of a main lens unit with respect to an
object plane to take an image. In this case, the resolution of the
image is equal to the number of the pixels of the image pickup
element. On the other hand, in the image pickup apparatus of the
present embodiment that obtains the light field, the resolution is
deteriorated compared to the number of the pixels of the image
pickup element.
[0034] FIG. 4B is a diagram of the projection on an image pickup
plane, i.e. the image-side conjugate plane 202 of the main lens
unit 101 with respect to the object plane 201, on conditions that
only the two-dimensional light intensity distribution of the pixels
in FIG. 4A is obtained. In the image pickup optical system of FIG.
2, the resolution that is obtained by taking an image with a pixel
pitch that is enlarged by the projection is provided. The spatial
resolution in this case is a value that is obtained by the
magnification |.sigma..sub.2/.sigma..sub.1| of the lens array 102
with reference to the original image pickup element 103 (the
magnitude of its square in a two-dimensional distribution). In the
embodiment, symbol .sigma..sub.1 denotes a distance from an
object-side principal plane of the lens array 102 to the image-side
conjugate plane 202 of the main lens unit 101 with respect to the
object plane 201, and symbol .sigma..sub.2 denotes a distance from
an image-side principal plane of the lens array 102 to the image
pickup element 103. In order to ensure an imaging angle of field
that is equivalent to the conventional image pickup optical system
that images the two-dimensional light intensity distribution with
the same image pickup element 103, the lens array 102 needs to be a
reduction system. When an image pickup element that is equivalent
to the image pickup element 103 is used for a lens array in an
enlargement system, information of both the position and angle of
field of the ray increase compared to the conventional image pickup
optical system. Therefore, the number of the pixels is
insufficient, and an imaging area is reduced compared to the
conventional image pickup optical system. In the present
embodiment, since the lens array 102 is the reduction system,
|.sigma..sub.1/.sigma..sub.2|>1 is met and the resolution of the
image is deteriorated compared to the number of pixels of the image
pickup element.
[0035] Next, the improvement of the spatial resolution by the pixel
shift effect will be described. As illustrated in FIG. 4A, the
angle of field that is viewed from each small lens of the lens
array 102 is overlapped on the image-side conjugate plane 202 of
the main lens unit 101 with respect to the object plane. The number
of the small lenses in which the angle of field is overlapped is
referred to as the overlap number of small lenses. In FIG. 4A,
three small lenses project a part of an area of the image-side
conjugate plane 202, and the overlap number of the small lenses is
three.
[0036] FIG. 4B is a diagram that is obtained by projecting a pixel
set of the image pickup element 103 corresponding to each small
lens on the image-side conjugate plane 202 of the main lens unit
101. As illustrated in FIG. 4B, when each of projection pixels is
shifted, they can be synthesized to reduce an apparent pixel size
and to obtain a high-resolution reconstructed image.
[0037] In other words, the lens array 102 only needs to be arranged
so that a pixel projected on the image-side conjugate plane 202 is
shifted from each other by a length different from an integer
multiple of the pitch of the projected pixels by adjacent lens
cells. Thus, the high-resolution image can be obtained. In other
words, pixel sets that are projected by the adjacent lens cells are
referred to as a first projection pixel set and a second projection
pixel set. In this case, the lens array 102 only needs to be
arranged so that projection positions of pixels that constitute the
first projection pixel set and the second projection pixel set do
not coincide with each other. In other words, the lens array 102
only needs to be arranged so that there is no pixel that is
projected on the same position of the pixels that are projected by
the adjacent lens array 102.
[0038] On the contrary, when the projection pixels coincide with
each other as illustrated in FIG. 4C, the pixel shift effect cannot
be obtained and therefore the resolution cannot be improved. The
highest resolution can be obtained by the pixel shift effect when a
ratio of the pixel shift corresponds to the overlap number of the
small lenses. Specifically, the overlap number is three in FIGS. 4A
to 4C, and therefore the highest resolution can be obtained when
the ratio of the pixel shift is 1/3 or 2/3. The details of the
relationship between the ratio of the pixel shift and the overlap
number of the small lenses will be described below.
[0039] Subsequently, the relationship between the distance
.sigma..sub.1 and the ratio of the pixel shift is obtained. A
relative pixel shift amount of adjacent small lenses is represented
by a ratio |.DELTA..sub.LA.sigma..sub.2/(.DELTA..sigma..sub.1)|
that is obtained by dividing a pitch .DELTA..sub.LA of the lens
array 102 by a pitch of the pixel that is projected on the
image-side conjugate plane 202 of the main lens unit 101. In the
embodiment, symbol .DELTA. denotes a pixel pitch of the image
pickup element 103. In order to recognize the behavior the pixel
shift amount with respect to the arrangement of the lens array,
referring to FIG. 5, a condition in which .sigma..sub.1 and
.sigma..sub.2 need to be met will be described.
[0040] FIG. 5 illustrates a detailed configuration of FIG. 1, and a
similar relationship is satisfied with respect to the configuration
of FIG. 2. Symbol F in FIG. 5 denotes an F-number of the main lens
unit 101, and symbol P.sub.ex denotes a distance between an exit
pupil (a paraxial exit pupil) of the main lens unit 101 and the
image-side conjugate plane 202 of the main lens unit 101. Symbol N
is a positive integer, which represents the division number of a
pupil plane of the main lens unit 101. Symbol P.sub.ex/(NF) denotes
a sampling pitch of angular information that is obtained by the
image pickup element 103. As can be seen in FIG. 5, the
relationship between .DELTA..sub.LA and .sigma..sub.1 meets the
following Expression (1).
.DELTA. LA = .sigma. 1 NF ( 1 ) ##EQU00001##
[0041] In the embodiment, symbol .sigma..sub.1 indicates a positive
value when the object-side principal plane of the lens array 102 is
disposed at a front side, i.e. an object side, of the image-side
conjugate plane 202, and on the other hand it indicates a negative
value when the object-side principal plane is disposed at a rear
side, i.e. an image side, of the image-side conjugate plane 202. A
dashed-dotted line in FIG. 5 represents a straight line that
connects a center of the small lens of the lens array 102 and an
edge of the pixel set corresponding to the small lens, and a
distance between an intersection of the straight line on the pupil
plane and a pupil center is given by the following Expression
(2).
P ex 2 F ( 1 + 1 - 2 l r N ) ( 2 ) ##EQU00002##
[0042] In the embodiment, symbol l.sub.r denotes a parameter that
represents a level of a dead zone and a crosstalk on the image
pickup element. Referring to FIGS. 6A and 6B, the dead zone and the
crosstalk will be described.
[0043] FIG. 6A illustrates a state of an image on the image pickup
element 103 when a value of l.sub.r is a negative value. White
regions indicate regions which a ray enters, and a gray region is
referred to as a dead zone, which is a region which the ray does
not enter. As the value of l.sub.r decreases, the dead zone is
expanded. Since it means that the number of pixels that do not
obtain information increases, it is preferred that the dead zone be
minimized. On the contrary, FIG. 6B illustrates a state of an image
on the image pickup element 103 when the value of l.sub.r is a
positive value. Images that are formed via different small lenses
are overlapped with each other. In the overlapped region, the rays
that have different positions and angles on the object plane 201
enter the same pixel, and this phenomenon is referred to as a
crosstalk. As the value of l.sub.r increases, the region of the
crosstalk is expanded. Since the pixel in which the crosstalk is
generated cannot obtain the light field, an exact image cannot be
generated if the pixel is used for the reconstruction.
[0044] When the pixel in which the crosstalk is generated is not
used for the reconstruction of the image, pixels that cannot be
used increase as the region of the crosstalk is large. Therefore,
it is preferred that the region where the crosstalk is generated be
minimized. When the value of l.sub.r is zero, the generations of
the dead zone and the crosstalk are minimized. In a real system,
however, due to the influence of a shift of the best focus position
caused by aberrations, vignetting of the main lens unit 101, light
falloff at edges, or the like, the generation of the dead zone or
the crosstalk may be suppressed even when the value of l.sub.r is
slightly shifted from zero.
[0045] Based on FIG. 5 and Expression (2), the following Expression
(3) is met.
N + 1 - 2 l r N P ex .sigma. 2 2 F ( P ex - .sigma. 1 ) = .DELTA.
LA 2 ( 3 ) ##EQU00003##
[0046] Therefore, using Expressions (1) and (3), the relative pixel
shift amount of the adjacent small lenses is given by the following
Expression (4).
.DELTA. LA .DELTA. .sigma. 1 / .sigma. 2 = 1 N ( N + 1 - 2 l r ) F
.sigma. 1 .DELTA. ( 1 - .sigma. 1 P ex ) ( 4 ) ##EQU00004##
[0047] Expression (4) is an expression that represents a behavior
of the relative pixel shift amount of the adjacent small lenses
with respect to the distance .sigma..sub.1.
[0048] Next, a sensitivity of the distance .sigma..sub.1 with
respect to the pixel shift effect will be described. The following
is a description of an example of the configuration illustrated in
FIG. 1, but the same is true for the configuration illustrated in
FIG. 2. Referring to Expression (4), the pixel shift amount with
respect to the distance .sigma..sub.1 is represented as FIG. 7.
Lozenge-shaped points in FIG. 7 represent solutions in which the
number of pixels of the pixel set corresponding to the small lens
is an integer. In the distance .sigma..sub.1 other than these
solutions, the crosstalk described above is generated. However, if
a wall surface is provided on the image pickup element 103 so that
the ray from a different small lens does not enter the pixel set
corresponding to a certain small lens, the crosstalk can be
suppressed even when the number of the pixel sets corresponding to
the small lens is not the integer. Since the shift of the integer
multiple of the pixels is meaningless as illustrated in FIG. 4C, an
integer portion in Expression (4) may be ignored. Therefore, a
ratio .delta. of the pixel shift is represented as the following
Expression (5).
.delta. = mod ( .DELTA. LA .sigma. 2 .DELTA..sigma. 1 , 1 ) ( 5 )
##EQU00005##
[0049] In Expression (5), z=mod(x,y) means that a value of z is
equal to a residue of a result obtained by dividing x by y.
[0050] FIG. 8 is a diagram of illustrating the ratio .delta. of the
pixel shift with respect to the distance .sigma..sub.1 that is
obtained by Expression (5) when a predetermined parameter is used.
The parameter that is used in FIG. 8 is a parameter in Embodiment 3
described below. Ideally, it is preferred that the lens array 102
be disposed at a position of the distance .sigma..sub.1 where the
ratio of the pixel shift that indicates the highest resolution is
obtained. In a real system, however, an error is contained in the
arrangement of the lens array 102, and the pixel shift effect is
reduced by the error. Therefore, it is preferred that the lens
array 102 be disposed at a position of the distance .sigma..sub.1
where the pixel shift effect does not easily change even when the
error is generated. Referring to Expression (4) and FIG. 7, the
ratio of the pixel shift can be represented by a quadratic function
with respect to the distance .sigma..sub.1. Therefore, the
deterioration of the pixel shift effect caused by the error of the
distance .sigma..sub.1 can be suppressed by preventing a portion of
both ends of the graph in FIG. 7 where the inclination is steep.
Thus, a condition that the sensitivity of the distance
.sigma..sub.1 is suppressed and that the high resolution is easily
obtained can be introduced.
[0051] In the present embodiment, the position where the lens array
102 is disposed meets the following Conditional Expression (6).
0.05 < .sigma. 1 P ex < 0.95 ( 6 ) ##EQU00006##
[0052] In the image pickup apparatus that has the configuration
illustrated in FIGS. 1 and 2, the high-resolution image can be
obtained by meeting Conditional Expression (6). If the value of
|.sigma..sub.1/P.sub.ex| is greater than the upper limit or smaller
than the lower limit of Conditional Expression (6), the
deterioration of the resolution caused by the error of the distance
.sigma..sub.1 easily occurs.
[0053] It is preferred that the range of the following Conditional
Expression (6a) be met to suppress the sensitivity of the distance
.sigma..sub.1 to easily achieve the high resolution.
0.18 < .sigma. 1 P ex < 0.82 ( 6 a ) ##EQU00007##
[0054] It is more preferred that the range of the following
Conditional Expression (6b) or (6c) be met to further suppress the
sensitivity of the distance .sigma..sub.1 to easily achieve the
high resolution.
0.30 < .sigma. 1 P ex < 0.70 ( 6 b ) 0.40 < .sigma. 1 P ex
< 0.60 ( 6 c ) ##EQU00008##
[0055] However, when the values of Conditional Expressions (6) and
(6a) to (6c) come close to 1, the resolution of the image obtained
by the image pickup element 103 is reduced since a magnification
|.sigma..sub.2/.sigma..sub.1| of the lens array decreases. Ideally,
when the n small lenses that have a pixel shift of 1/n are
overlapped, the resolution is magnified n times. In the embodiment,
n is a positive integer. In the real system, however, an
improvement amount of the resolution by the pixel shift effect is
smaller than that of the ideal system due to the influences of a
noise or aberrations of the main lens unit 101. Therefore, it is
preferred that the resolution of the image obtained by the image
pickup element 103 be ensured to some extent. In the configuration
illustrated in FIG. 1, when the value of Conditional Expression (6)
comes close to 1, there is a case where the lens array interferes
with the main lens unit 101. Accordingly, it is more preferred that
the upper limits of Conditional Expressions (6) and (6a) to (6c) be
set to be smaller than 0.1 to suppress the sensitivity to obtain a
further high-resolution light field.
[0056] Next, a condition that can obtain the pixel shift effect
will be considered. As described above, when the relative pixel
shift amount of the adjacent small lenses that is represented by
Expression (4) is an integer, the pixel shift effect cannot be
obtained as illustrated in FIG. 4C. Therefore, the lens array 102
may be disposed so that a shift of the projection pixel of two
small lenses adjacent to each other is not an integral multiple of
the projection pixel when the pixel of the image pickup element 103
is projected on the image-side conjugate plane 202.
[0057] Subsequently, a condition that obtains a higher pixel shift
effect is obtained. First of all, the overlap number of the small
lenses is estimated. FIG. 9 is a graph that has a horizontal axis
indicating the number j of the small lens illustrated in FIG. 4B
and that has a vertical axis indicating a coordinate y on the
image-side conjugate plane 202 of the main lens unit 101 with
respect to the object plane 201. In the embodiment, j=0 may be an
arbitrary small lens of the lens array 102. Each of straight lines
parallel to a y-axis in FIG. 9 represents a coordinate that is
obtained when the pixel set corresponding to the j-th small lens is
projected on the image-side conjugate plane 202. A dashed-dotted
line A connects points indicating the upper limits of these
straight lines, and a dashed-dotted line B connects points
indicating the lower limits of these straight lines. The
dashed-dotted line A is given by
y=.DELTA..sub.LA{j+|.sigma..sub.1/(2.sigma..sub.2)|}, and the
dashed-dotted line B is given by
y=.DELTA..sub.LA{j-|.sigma..sub.1/(2.sigma..sub.2)|}. The number of
the overlapped small lenses corresponds to a gap between the
dashed-dotted lines A and B in a j direction, and the number can be
estimated at around |c.sub.1/.sigma..sub.2|+1 when the small lens
of j=0 is also counted.
[0058] Subsequently, the spatial resolution including the pixel
shift effect is obtained. As described above, in the real system,
the improvement amount of the resolution by the pixel shift effect
is smaller than that of the ideal system. However, for easy
description, the improvement of the resolution in the ideal system
will be described in the present embodiment. A final resolution is
defined to be determined by the largest pixel of the pixels that
become apparently small by the pixel shift effect. The pixel size
is referred to as the maximum value of the apparent pixels.
[0059] For example, when the overlap number of the small lenses is
eight and the ratio .delta. of the pixel shift of the adjacent
small lenses that is represented by Expression (5) is 0.45, the
pixel shifts of the eight small lenses are 0, 0.45, 0.90, 0.35,
0.80, 0.25, 0.70, and 0.15, respectively. In this case, the maximum
value of the apparent pixels that determines the resolution is
0.70-0.45=0.25. Next, a case in which the overlap number is the
same and the ratio .delta. is 3/8 is considered. In this case, the
pixel shifts of the eight small lenses are 0, 3/8, 6/8, 1/8, 4/8,
7/8, 2/8, and 5/8, respectively. In this case, the maximum value of
the apparent pixels is 1/8, which is identical to the inverse of
the overlap number. Therefore, when the ratio of the shift of the
pixel where the adjacent small lens projects is identical to the
inverse of the overlap number of the small lenses, the largest
pixel shift effect is obtained. The same is true for a case where
the ratio .delta. represented by Expression (5) is 1/8, 5/8, or
7/8. However, when the ratio .delta. is 2/8, 4/8, or 6/8, the pixel
shift effect is deteriorated. For example, the case where the ratio
.delta. is 2/8 is considered. In this case, the pixel shifts of the
eight overlapped small lenses are 0, 2/8, 4/8, 6/8, 0, 2/8, 4/8,
and 6/8, respectively, and the maximum value of the apparent pixels
is 2/8=1/4 since the pixels are overlapped with each other.
Therefore, the pixel shift effect is half compared to the case
where the ratio .delta. is 1/8, 3/8, 5/8, or 7/8.
[0060] Accordingly, when the ratio .delta. given by Expression (5)
is equal to m.sub.0/M.sub.0, the largest pixel shift effect can be
obtained. In the embodiment, symbol M.sub.0 denotes the overlap
number of the small lenses, and symbol m.sub.0 denotes an integer
that is smaller than M.sub.0, where the greatest common factor of
m.sub.0 and M.sub.0 is 1. As described above, the overlap number
M.sub.0 can be estimated at around |.sigma..sub.1/.sigma..sub.2|+1,
and the pixel shift effect is improved as the ratio .delta. comes
close to m.sub.0/M.sub.0.
[0061] FIG. 10 is a diagram of illustrating a relationship between
the maximum value of the apparent pixels with respect to the
distance .sigma..sub.1 and the inverse of the overlap number of the
small lenses using the same parameter as that of FIG. 8. As the
maximum value of the apparent pixels represented by a
lozenge-shaped point and the inverse of the overlap number of the
small lenses represented by a dashed line are close to each other
with respect to the distance .sigma..sub.1, the pixel shift effect
is heightened and the resolution of the reconstructed image is
improved. On the contrary, in the distance .sigma..sub.1 where the
maximum value of the apparent pixels and the inverse of the overlap
number of the small lenses are distant from each other, a large
pixel shift effect cannot be obtained. FIG. 11 is a relationship
between the distance .sigma..sub.1 and the spatial resolution ratio
when the same parameter as that of FIG. 8 is used. The spatial
resolution ratio of the vertical axis is indicated by normalizing
the spatial resolution of the reconstructed image by the number of
the pixels of the image pickup element. As the lozenge-shaped point
and the inverse of the overlap number of the small lenses are close
to each other with respect to the distance .sigma..sub.1 in FIG.
10, the resolution including the pixel shift effect is improved. On
the contrary, in the distance .sigma..sub.1 where the maximum value
of the apparent pixels is closer to 1 in FIG. 10, the improvement
of the resolution by the pixel shift effect is scarcely shown. As
described above, as the distance |.sigma..sub.1| comes close to
P.sub.ex/2, the fluctuation of the spatial resolution ratio is
gentle and the sensitivity of the lens array is suppressed.
[0062] Thus, Conditional Expression (7) that is used for
efficiently obtaining the improvement of the resolution by the
pixel shift effect can be obtained.
0.9 < M m mod ( .DELTA. LA .sigma. 2 .DELTA..sigma. 1 , 1 ) <
1.1 ( 7 ) ##EQU00009##
[0063] In Conditional Expression (7), symbol M denotes an integer
that meets the following Conditional Expression (8).
0.2 < M 1 + .sigma. 1 / .sigma. 2 < 2.0 ( 8 )
##EQU00010##
[0064] Symbol m denotes an integer that is smaller than the integer
M, and the greatest common factor of m and M is 1. Conditional
Expressions (7) and (8) represent the level of the pixel shift
effect, and the high-resolution of the reconstructed image can be
achieved by meeting Conditional Expressions (7) and (8). If the
values of
(M/m)mod(|.DELTA..sub.LA.sigma..sub.2/.DELTA..sigma..sub.1|,1) and
M/(1+|.sigma..sub.1/.sigma..sub.2|) are greater than the upper
limit or smaller than the lower limit of Conditional Expressions
(7) and (8) respectively, a sufficient pixel shift effect cannot be
obtained and therefore the improvement of the spatial resolution is
insufficient.
[0065] It is preferred that the following Conditional Expression
(7a) be met in order to obtain a higher resolution image.
0.93 < M m mod ( .DELTA. LA .sigma. 2 .DELTA..sigma. 1 , 1 )
< 1.07 ( 7 a ) ##EQU00011##
[0066] It is more preferred that the following Conditional
Expression (7b) be met in order to obtain a further high-resolution
image.
0.95 < M m mod ( .DELTA. LA .sigma. 2 .DELTA..sigma. 1 , 1 )
< 1.05 ( 7 b ) ##EQU00012##
[0067] More preferably, the following Conditional Expression (8a)
or 8 (b) is met in order to obtain a larger pixel shift effect.
0.4 < M 1 + .sigma. 1 / .sigma. 2 < 1.6 ( 8 a ) 0.6 < M 1
+ .sigma. 1 / .sigma. 2 < 1.4 ( 8 b ) ##EQU00013##
[0068] It is preferred that the image-side surface of the small
lens that constitutes the lens array 102 have a convex shape. Thus,
the astigmatism of the lens array 102 is suppressed and the
sensitivity with respect to the resolution can be decreased. On the
contrary, when the image-side surface does not have the convex
shape, the astigmatism is large, and the periphery of the image
formed by each small lens is blurred. If the blurred portion is
used for the reconstruction processing, the reconstructed image is
not formed sharply. It is more preferred that the object-side
surface of the small lens that constitutes the lens array 102 have
a plane or convex shape. Thus, the curvature of the small lens
moderates and the aberrations are suppressed, and therefore the
sensitivity can be further decreased.
[0069] It is preferred that the lens array 102 be disposed at the
object side relative to the image-side conjugate plane 202 of the
main lens unit 101 with respect to the object plane 201. As can be
seen from the comparison of FIGS. 1 and 2, it is because the
configuration of FIG. 1 can reduce the total length of the image
pickup optical system compared to the configuration of FIG. 2.
Furthermore, in the configuration of FIG. 1, an image height where
an off-axis ray enters the lens array 102 and the image pickup
element 103 is smaller than that in the configuration of FIG. 2. As
described above, the size of the image pickup optical system can be
reduced by adopting the arrangement as illustrated in FIG. 1.
[0070] Other effects of the present embodiment are that an image in
which the resolution is optically improved can be obtained by
meeting a condition that has an appropriate relationship between
the lens array and the image pickup element.
[0071] In the image pickup optical systems illustrated in FIGS. 1
and 2, an image in which small images having different imaging
viewpoints and imaging regions are arrayed is obtained by the image
pickup element. An image having different focus positions,
F-numbers, or viewpoints can be obtained by a method of weighting
all or a part of these images or a method of overlapping these
images while shifting them (a reconstruction method). For example,
this method is disclosed in "Light Field Photography with a
Hand-held Plenoptic Camera" (Ren Ng, et al., Stanford Tech Report
CTSR 2005-02). Therefore, the description of the method is omitted
in the embodiment. The configuration of the present embodiment is
slightly different from the above literature, but there is
essentially no difference between them since the configuration of
dividing the pupil of the main lens unit is the same. Therefore, an
image in which the focus position, depth of field, or imaging
viewpoint is changed can be generated by using the similar
reconstruction method. Also in this case, the high-resolution
reconstructed image can be obtained by using the pixel shift
effect. The reconstruction processing may also be performed by an
image processing apparatus that is separated from the image pickup
apparatus.
[0072] A person or an object does not have to exist on the object
plane 201 that is illustrated in FIGS. 1 and 2. This is because the
focusing on the person or the object that exists in back of or in
front of the object plane 201 can be performed by the
reconstruction processing after taking an image. The main lens unit
101 may also consist of one lens.
Embodiment 1
[0073] Next, referring to FIG. 12, an image pickup apparatus (an
image pickup optical system) in Embodiment 1 will be described.
FIG. 12 is a cross-sectional diagram of the image pickup optical
system in the present embodiment. In FIG. 12, the main lens unit
101 is a single focus lens, which includes an aperture stop SP that
controls the F-number at the time of taking an image. However, in
order to obtain many parallax information, it is preferred that the
aperture diameter be large. In the present embodiment, the aperture
diameter may also be fixed since the F-number can be changed by the
reconstruction after taking the image.
[0074] The main lens unit 101 is provided with a focus mechanism in
accordance with specifications. When the main lens unit 101
includes the focus mechanism, a lens position is controlled by an
autofocus (AF) mechanism or a manual focus mechanism (not shown).
In the present embodiment, a focusing after taking an image
(refocusing) can be performed by the image processing, but the
parallax information that is obtained by the image pickup element
103 is limited since the aperture diameter is limited. Therefore, a
range in which the refocusing can be performed is also limited. The
refocusing range can be shifted in a depth direction by changing
the focus position at the time of taking the image.
[0075] The lens array 102 has a positive refractive power and is
configured by a spherical solid lens whose both surfaces have a
convex shape. One of the two sides of the small lens of the lens
array 102 may also have a plane or have an aspherical curved
surface. It may also be configured by arraying liquid lenses,
liquid crystal lenses, diffractive optical elements, or the like.
The lens array 102 forms an image on the image pickup element 103
by viewing the image formed by the main lens unit 101 as a virtual
object.
[0076] In the present embodiment, the distance P.sub.ex from the
exit pupil of the main lens unit 101 to the image-side conjugate
plane 202 of the main lens unit 101 is equal to 66.4357 (mm), the
pitch .DELTA..sub.LA of the lens array 102 is equal to 4.3559 (mm),
and the pixel pitch .DELTA. of the image pickup element 103 is
equal to 0.0043 (mm). The lens array 102 is disposed so that the
distance .sigma..sub.1 is equal to 37.7657 (mm) and the distance
.sigma..sub.2 is equal to 5.4325 (mm). In such a configuration, the
large pixel shift effect is obtained and therefore the
high-resolution image can be obtained. In addition, the arrangement
sensitivity of the lens array 102 with respect to the pixel shift
effect can also be suppressed. The high-resolution using the pixel
shift effect is also achieved for the reconstructed image in which
the F-number, the focus position, or the depth of field is changed.
A further high-resolution image may be obtained along with image
estimation such as MAP (Maximum a posteriori) estimation at the
time of reconstructing the image.
Embodiment 2
[0077] Next, referring to FIG. 13, an image pickup apparatus (an
image pickup optical system) in Embodiment 2 will be described.
FIG. 13 is a cross-sectional diagram of the image pickup optical
system in the present embodiment. In FIG. 13, the main lens unit
101 is a single focus lens. The lens array 102 is configured by a
surface having a plane at the object side and a surface having a
convex shape at the image side, which reforms an image formed by
the main lens unit 101 on the image pickup element 103.
[0078] In the present embodiment, the distance P.sub.ex from the
exit pupil of the main lens unit 101 to the image-side conjugate
plane 202 of the main lens unit 101 is equal to 66.4357 (mm), the
pitch .DELTA..sub.LA of the lens array 102 is equal to 0.3784 (mm),
and the pixel pitch .DELTA. of the image pickup element 103 is
equal to 0.0043 (mm). The lens array 102 is disposed so that the
distance .sigma..sub.1 is equal to -5.4679 (mm) and the distance
.sigma..sub.2 is equal to 1.0036 (mm). Since the conjugate plane of
the lens array 102 with respect to the image pickup element 103,
i.e. the image-side conjugate plane 202 of the main lens unit 101
with respect to the object plane 201, exists at the object side
relative to the lens array 102, the distance .sigma..sub.1 is a
negative value.
[0079] According to the present embodiment, an image pickup
apparatus that suppresses the arrangement sensitivity of the lens
array and that achieves efficient high-resolution using the pixel
shift effect can be provided.
Embodiment 3
[0080] Next, referring to FIG. 14, an image pickup apparatus (an
image pickup optical system) in Embodiment 3 will be described.
FIG. 14 is a cross-sectional diagram of the image pickup optical
system in the present embodiment. In FIG. 14, the main lens unit
101 is a zoom lens, and the lens array 102 is configured by a
biconvex positive lens, which forms an image on the image pickup
element 103 by viewing the image formed by the main lens unit 101
as a virtual object.
[0081] The main lens unit 101 is configured by a first lens unit L1
having a positive refractive power, a second lens unit L2 having a
positive refractive power, a third lens unit L3 having a negative
refractive power, a fourth lens unit L4 having a positive
refractive power, and a fifth lens unit L5 having a positive
refractive power, in order from the object side. When the
magnification is varied, the first lens unit L1 and the fifth lens
unit L5 are fixed and the second lens unit L2, the third lens unit
L3, and the fourth lens unit L4 move on an optical axis.
[0082] In the present embodiment, at a wide-angle end of the main
lens unit 101, the distance P.sub.ex from the exit pupil of the
main lens unit 101 to the image-side conjugate plane 202 of the
main lens unit 101 is equal to 133.8129 (mm), the pitch
.DELTA..sub.LA of the lens array 102 is equal to 1.9776 (mm), and
the pixel pitch .DELTA. of the image pickup element 103 is equal to
0.0064 (mm). FIGS. 7 and 9 described above illustrate the ratio 5
of the pixel shift and the resolution including the pixel shift
effect using these parameters and N=7 and l.sub.r=0.5. Since an
aperture stop (not shown) is installed at the small lens of the
lens array 102, the crosstalk does not occur even when l.sub.r is
equal to 0.5. The lens array 102 is disposed so that the distance
.sigma..sub.1 is equal to 40.1453 (mm) and the distance
.sigma..sub.2 is equal to 4.0145 (mm).
[0083] According to the present embodiment, an image pickup
apparatus that suppresses the arrangement sensitivity of the lens
array and that achieves efficient high-resolution using the pixel
shift effect can be provided.
Embodiment 4
[0084] Next, referring to FIG. 15, an image pickup apparatus in
Embodiment 4 will be described. FIG. 15 is a configuration diagram
of an image processing system in the present embodiment. As
illustrated in FIG. 15, the image processing system includes an
image pickup apparatus 301. The image pickup apparatus 301 includes
the image pickup optical system of Embodiment 3 that is illustrated
in FIG. 14. An image processing apparatus 302 is a computer device
that performs the image reconstruction described above. A
predetermined reconstruction processing is performed for an image
obtained by the image pickup apparatus 301 using the image
processing apparatus 302, and then the image is outputted to one or
a plurality of an output device 305, a display device 304, and a
storage medium 303. The storage medium 303 is, for example a
semiconductor memory, a hard disk, or a server on a network. The
output device 305 is for example a printer. The display device 304
is connected to the image processing apparatus 302, and the
reconstructed image is inputted to the display device 304. A user
can work while confirming the reconstructed image via the display
device 304.
[0085] Image processing software 306 has a function that performs a
development processing and other image processings if needed, as
well as the reconstruction processing described above. The display
device 304 is for example a liquid crystal display or a projector.
In particular, when the display device 304 is a DLP (Digital Light
Processor) type projector that uses a DMD (Digital Micro-mirror
Device), an optical system in the projector may also be configured
similarly to FIG. 14. In this case, the optical system in the
projector can adopt the configuration where the DMD is installed
instead of the image pickup element 103 of FIG. 14. In this case,
instead of inputting the reconstructed image to the display device
304, the image obtained by the image pickup element 103 of the
image pickup apparatus 301 can be inputted as it is. Since the
conversion at the time of image projection is performed inversely
with a case of taking an image, an image that is automatically
reconstructed is outputted onto a screen. In addition, since the
pixel shift effect is generated on a conjugate plane of the DMD
with respect to the lens array 102, a high-resolution output image
can be similarly obtained. According to the present embodiment, an
image pickup apparatus and an image processing system that suppress
the arrangement sensitivity of the lens array and that achieve the
efficient high-resolution can be provided.
[0086] While the present invention has been described with
reference to embodiments, it is to be understood that the invention
is not limited to the disclosed embodiments. The scope of the
following claims is to be accorded the broadest interpretation so
as to encompass all such modifications and equivalent structures
and functions. For example, even when the present invention is
applied to an image pickup optical system that is removable from an
image pickup apparatus having an image pickup element, the image
pickup optical system capable of obtaining the high-resolution
light field with a simple configuration can be provided by using
the image pickup optical system and the image pickup element that
meet the relationship described above.
[0087] Numerical data (numerical example) of the main lens unit in
each of the embodiments described above (Embodiments 1 to 4) will
be described as follows. Symbol i denotes an order of a surface
from the object side, symbol r.sub.i denotes a radius of curvature
of an i-th surface, symbol d.sub.i denotes a lens thickness or an
air gap between the i-th surface and the (i+1)th surface, and
symbols n.sub.i and v.sub.i denote a refractive index and Abbe
number for d-line, respectively. In Table 1, values of Conditional
Expressions (6), (7), and (8) in each of the numerical examples
(Embodiments 1 to 4) will be indicated.
NUMERICAL EXAMPLES
TABLE-US-00001 [0088] (EMBODIMENTS 1 and 2) Unit [mm] Surface data
Surface Effective Number r d nd vd diameter 1 89.763 1.80 1.84666
23.8 40.57 2 35.283 9.50 1.58913 61.2 38.63 3 -104.031 0.15 38.18 4
45.845 3.80 1.77250 49.6 34.85 5 205.586 1.60 34.09 6 190.384 1.50
1.80010 35.0 32.16 7 57.059 3.26 30.16 8 -88.455 1.50 1.56873 63.2
30.22 9 23.683 3.50 1.84666 23.8 28.33 10 37.253 19.26 27.84 11
-380.953 3.00 1.84666 23.8 28.98 12 -70.178 10.00 29.11 13 .infin.
22.12 26.48 14 -37.638 1.20 1.78472 25.7 21.81 15 57.202 4.30
1.52249 59.8 22.35 16 -38.872 0.30 22.71 17 -249.784 2.50 1.77250
49.6 22.78 18 -59.162 0.20 22.89 19 56.254 3.50 1.80400 46.6 22.42
20 -100.510 1.50 21.91 21 -109.205 2.80 1.84666 23.8 20.71 22
-44.064 0.16 20.09 23 -42.571 1.20 1.60311 60.6 19.94 24 41.456
8.27 18.54 25 -84.040 7.29 1.62230 53.2 15.96 26 -19.904 0.15 15.00
27 -19.678 2.00 1.59270 35.3 14.85 28 -118.544 0.00 14.29 29
.infin. (variable) 14.22 Image plane .infin. Various kinds of data
Zoom ratio 1.00 Focal length 99.96 F-number 2.89 Angle of field
8.31 Image height 14.60 Total lens length 156.82 BF 40.46 d29 40.46
Entrance pupil position 117.08 Exit pupil position -25.97 Front
side principal point position 66.63 Rear side principal point
position -59.50 Zoom lens unit data Front side Rear side Start
Focal Lens configuration principal principal Unit surface length
length position position 1 1 99.96 116.36 66.63 -59.50 Single lens
data Start Focal Lens surface length 1 1 -69.72 2 2 45.88 3 4 75.59
4 6 -102.35 5 8 -32.69 6 9 68.67 7 11 101.16 8 14 -28.77 9 15 44.99
10 17 99.78 11 19 45.31 12 21 85.56 13 23 -34.64 14 25 40.16 15 27
-40.11
TABLE-US-00002 (EMBODIMENTS 3 and 4) Unit [mm] Surface data Surface
Effective number r d nd vd diameter 1 124.447 2.80 1.74950 35.0
69.47 2 75.819 0.15 66.70 3 75.787 12.51 1.49700 81.6 66.68 4
-374.867 0.10 65.27 5 78.754 3.65 1.49700 81.6 62.96 6 102.655
(variable) 62.09 7 54.676 2.20 1.84666 23.8 49.13 8 47.526 1.22
47.37 9 55.346 7.65 1.48749 70.2 47.31 10 1833.147 (variable) 46.11
11 -401.208 1.40 1.80400 46.6 34.13 12 38.875 6.37 32.30 13 -92.113
1.34 1.48749 70.2 32.44 14 39.755 5.23 1.85026 32.3 33.61 15
292.638 4.06 33.53 16 -71.105 4.46 1.84666 23.8 33.56 17 -36.898
1.00 1.72000 46.0 34.09 18 311.857 (variable) 35.08 19 141.625 3.59
1.71300 53.9 35.92 20 -238.303 0.15 36.12 21 431.096 5.95 1.49700
81.6 36.23 22 -48.826 1.00 1.85026 32.3 36.30 23 -140.339
(variable) 36.87 24 81.141 3.98 1.80400 46.6 37.24 25 19006.920
1.15 36.96 26(stop) .infin. 15.08 36.64 27 45.384 7.49 1.49700 81.6
31.66 28 -839.909 5.33 1.62588 35.7 29.72 29 39.178 23.47 26.68 30
139.400 5.78 1.50378 66.8 25.86 31 -105.607 7.43 26.94 32 -40.699
1.00 1.80100 35.0 28.35 33 -79.231 0.15 29.36 34 115.417 4.09
1.83400 37.2 30.71 35 -493.918 (variable) 31.15 Image plane .infin.
Various kinds of data Zoom ratio 2.67 Wide-angle Intermediate
Telephoto Focal length 72.49 99.90 193.91 F-number 2.90 2.90 2.90
Angle of field 16.59 12.20 6.36 Image height 21.60 21.60 21.60
Total lens length 243.50 243.51 243.49 BF 52.10 52.11 52.08 d 6
8.38 11.42 33.14 d10 1.59 10.49 16.84 d18 30.54 23.46 1.50 d23
11.11 6.25 0.15 d35 52.10 52.11 52.08 Entrance pupil position 96.84
140.42 236.01 Exit pupil position -81.71 -81.71 -81.71 Front side
principal position 130.06 165.74 148.88 Rear side principal
position -20.39 -47.79 -141.83 Zoom lens unit data Front side Rear
side Start Focal Lens configuration principal principal Unit
surface length length position position 1 1 179.99 19.21 2.38
-10.26 2 7 155.92 11.07 -0.28 -7.84 3 11 -27.99 23.86 4.82 -11.76 4
19 124.89 10.69 0.62 -6.15 5 24 86.42 74.95 21.42 -59.06 Single
lens data Start Focal Lens surface length 1 1 -265.43 2 3 128.02 3
5 647.74 4 7 -499.75 5 9 116.90 6 11 -44.02 7 13 -56.78 8 14 53.60
9 16 85.48 10 17 -45.77 11 19 125.08 12 21 88.61 13 22 -88.51 14 24
101.34 15 27 86.88 16 28 -59.67 17 30 120.22 18 32 -105.70 19 34
112.52
TABLE-US-00003 TABLE 1 CONDITIONAL CONDITIONAL CONDITIONAL
EXPRESSION(6) EXPRESSION(7) EXPRESSION(8) EMBODI- 0.57 0.96 0.50
MENT 1 EMBODI- 0.08 1.06 1.55 MENT 2 EMBODI- 0.30 1.00 0.91 MENT 3
EMBODI- 0.30 1.00 0.91 MENT 4
[0089] This application claims the benefit of Japanese Patent
Application No. 2011-052352, filed on Mar. 10, 2011, which is
hereby incorporated by reference herein in its entirety.
* * * * *